Polymerization of hydrocarbon gases



Feb. 7, 1939. F. w. SULLIVAN, JR., 'ET AL 2,145,900

POLYMERIZATION OF HYDROCARBON GASES Filed Nov. 25, 1931 gg \m JzedezMwJuZZwdmL/Z Patented Feb. 7, 1939.

PATENT OFFICE POLYMERIZATION OF GAS ESHYDROCARBON Frederick w. Sullivan, Jr., and Robert F. nutrirnfl', Hammond, Ind.,

Oil Company, Chi

Indiana Application November 25,

13 Claims.

This invention relates to improvements in the polymerization of unsaturated gases and it pertains more particularly to a method for obtaining from petroleum oil and gases increased yields of gasoline of greatly improved characteristics.

We have discovered that when light olefins are polymerized in a continuous system in the presence'of naphtha or a similar absorber oil at temperatures upwards of 900 F. and pressures upwards 01' 500 pounds per square inch, high yields of liquid products are obtained which contain -large amounts of gasoline having an extraordinarily high knock rating. V Our invention should not be confused with the idea of circulating natural gases or refinery gases containing no olefins or only-small proportions 1 thereof with gas oil through pyrolytic cracking systems wherein the temperature and pressure ,conditions are dissimilar and wherein the eflect m of the gas ismerely to obtain agitation or to repress gas formation by a mass action efiect. Our invention deals with reactions under high pressures and with gaseshaving relatively large olefin contents.

It appears that when the oil and the gas are brought together under such conditions a mutual activation and interaction takes place. It is possible that the oil, despite the fact that it would not under these conditions by itself show any large conversion to gasoline of higher antiknock value, is nevertheless in a sensitive or active state. Under these conditions the presence of the reactive olefins present in the gas is suflicient to bring about the conversion of the oil by combina ing with the constituents thereof which are sensitized or activated. We do not limit ourselves to any theory in our attempt to explain the phe-.

nomena ;.but it should. be understood that our results cannot be explainedon the basis otpyrolytic cracking.

The accompanying, drawing illustrates diagrammatically (in the manner of a flow sheet) our improved-polymerization system.

. When our oleflns are obtained from saturated hydrocarbon gases such as ethane, propane, bu-

tane, etc. the 'saturated gases are introduced through line it into heater II where they are heated at pressures up to 200 pounds per square inch and up to temperatures of from '1400 to 1600 degrees F. or thereabouts, following which they may be passed through a line I2 and soaking chamber II to effect further conversion. The soaking chamber may be cut out by closing valves II and I4, the gases then being passed through i line I! (by opening valves l6 and it) directly assignors to Standard 111., a corporation of 1931, semi No. 577,228

through cooler or exchanger [1. when cooled the gases pass through valve II and line It to compressor 2|.

It a supp y of olefin containing gases from some outside source is available these gases enter the system through line 2| and valve 2Ia. Light hydrocarbons from a stabilizing plant may be used directly or may be cracked as above stated. We may use gases ,from vapor phase oil cracking operations, which gases may have the following composition:

Per cent Methane and hydrogen 35.4 Ethylene 22.9 Ethane 13.3 Propylene 18.1 Propane 0 Butylenes 5.5 Butanes 1.4 Higher hydrocarbons 3.4

The gases from either orboth sources are compressed in compressor 20 to 100-3000 pounds per square inch, after which the gases may take either of two courses. They may be cooled in cooler 22 and passed through line 23 .to scrubber 24 where they are contacted with an absorber oil such as naphtha, or polymerized or hydrogenated hydrocarbons of equivalent boiling range; the absorber oil being introduced through line 25 by pump 20 which is supplied with fresh charging stock from line 21 or from line 28. Fuel gas containing primarily hydrogen and methane, but which may contain certain amounts of higher hydrocarbon gases,

is eliminated from scrubber 24 through valve take-oil. line solved pimple-hydrocarbon gases is withdrawn from the scrubber by actor II which of 750 to 3900110 24a. The solvent charged with disso with recycled stock line 29 and is injected by. Pump 1M0 the polymerization heater and re; I

per square inch. Alternatively; the compressed oleflnic gases may be introduced directly -i'rom compressor 20 into reactor 3| which case valve 20a is closed and valve'l'lo'is opened so that the absorber oil is the reactor by means of pump 30.-

The reactor may be an elongated closed,con-- duit such as a pipe still and it may also include an enlarged portion or reaction chamber to obtain the desired time oi contact. This time may vary up to twenty minutes depending on reaction conditions: at temperatures of about 950 F. and pressures of about 800 pounds per square inch the optimum time or contact appears to be about 'throughpipe 32 in introduced into 1 to 2 minutes. The. reaction products are removed through line 33, their pressure is reduced by valve 34, and they are then passed into fractionating tower 35. From this tower high boiling liquid products (higher than the gasoline boiling range) are removed by line and they may either'be eliminated through line 31 orreturned through line 38, cooler 38' and pipe 28 back to the scrubber tower 24. Alternatively, valve 39 may be closed and all or part of the heavy polymerized oil from line 38 may be introduced through line 40 back to the reactor 3|,

so that the heavy stock may be subjected to further treatment in the presence of more olefin gases. Uncondensed gases and vapors of light products (gasoline, etc.) are removed from frac-' tionating tower 35 by line 41 and the light products are condensed in cooler 42 and separated fromuncondensed gases in separator 43. The separated light liquid products pass through line 44 to the stabilizer 45, which-is provided with a suitable reboiling and iractionating means (not shown). Uncondensed gases are removed from separator 43 by line 46. These gases may be discarded through valve 46a or they may be recycled through pipe 41, recompressed, and reused. They may, on the other hand, be returned by pipe 49 to the inlet 10 of the gas cracking heater ll whereby their olefin content will be increased prior to returning them to the scrubber and reaction system. v

Finished gasoline is removed from stabilizer 45 through pipe 50 and uncondensed gases are removed therefrom through pipe I. The uncondensed gases may be eliminated from the system through valve 5Ia or they may be passed through line 52 into line l0, and thence through the cracking and polymerization system. Alternatively, they may be passed through line 53 to line l8 and compressor 20 for recycling. The stabilizer gases withdrawn through line 5| and recycled with the aid of line 53 are intermediate in volatility between the gases removed from the top of separator 43 and the motor fuel withdrawn from the bottom of the stabilizer.

In order to bring out the remarkable results obtained by polymerizing olefins in the presence of naphtha, and the like, we will state the results of some of our work. In the following example products.

one or two parts by weight of olefin gases were polymerized with one part absorber oil at a pressure of 800 pounds and a temperature of 950 F. in a continuous system. The liquid yield percentages are based on the amount by weight of liquid absorbing oil charged into the system.

A. When heavy naphtha with a knock rating of about 30 was treated for two minutes with gases containing 45% olefins, it yielded 125% liquids of which 91% was gasoline having a knock rating of 65.

It will be noted in the above example that we have obtained extremely high yields of liquid Furthermore, it will be noted that the gasoline obtained is characterized by an extremely high increase in anti-knock value.

1 Another extremely important feature of our invention is the'fact'that the polymerization reaction-is readily feoritrolled, i. e. there is no tendency for the temperature to "run away. The reaction appears to be in the vapor phase because of the presence of the relatively large amountsof gas present. The concentration of olefins should be as high as possible, and we have found that gases containing upwards of 95% olefins give excellent results.

The time of contact is important and if, for instance, in the above example the time is increased to or minutes the yield falls off rapidly and the knock rating of the gasoline is lowered. Shorter times of contact are relatively ineffective.

A particular feature of the invention is the use of a continuous system utilizing gases which are available in commercial quantities, and absorber oils which would otherwise require further pyrolitic cracking to render them suitable for high antiknock motor fuels. By our process the naphtha feed stock or virgin naphtha is sensitized or activated in the presence of gases which evidently react with it to yield the high grade motor fuel, and the continuous feature makes it possible to accurately regulate the heating and cooling rates, reaction periods, etc. on a commercial scale.

The term absorber oil as used in this specification and in the following claims is hereby de- 1. The method of producing gasoline of high knock rating from low knock rating naphtha and normally gaseous olefinic hydrocarbons which comprises scrubbing a compressed hydrocarbon gas mixture containing olefins with at least a part of said low knock rating naphtha so as to concentrate the olefin content thereof to at least 25% olefins, charging said concentrated olefinic gases with said low knock rating naphtha to a reaction zone at a temperature of 950 to 1150 F. and a pressure of 750 to 3000 pounds per square inch for a period of'time of about 1 /2 to 2 minutes, rectifying the converted material to obtain low boiling uncondensed gases, high antiknock gasoline and a fraction of hydrocarbons intermediate in volatility between 'the low boiling uncondensed gases and the high anti-knock gasoline, and returning the said intermediate fraction of hydrocarbons for reprocessing.

2. The method of producing gasoline of high knock rating from low knock rating virgin naphtha and normally gaseous olefinic hydrocarbons which comprises charging said low knock rating naphtha together with a compressed hydrocarbon gas mixture substantially free of hydrogen and methane containing at least 25% olefins to a reaction zone at a temperature of 900 to 1200 F.

. and a pressure of 800to 3000 pounds per square inch for a period of time sufiicient to simultaneously convert the low knock rating naphtha and gaseous olefinic hydrocarbons into high knock rating gasoline, rectifying the total converted material to obtain low boiling uncondensed gases, high knock rating gasoline and a fraction of hy-' drocarbons intermediate in volatility between the ing gas substantially free of hydrogen and methane to a heating zone and heating same to a temperature of about 900 to 1200 F. while under a pressure of about 800 to 3000 poundsper square inch'to effect a mutual activation and interaction of the oleflns and naphtha, releasing the pressure a on the reaction products and rectifying the converted material to obtain low boiling uncon-' densed gases, high knock rating gasoline and a fraction of hydrocarbons intermediate in volatility between the low boiling uncondensed gases and high knock rating gasoline, and returning the said intermediate fraction of hydrocarbons for reprocessing.

4. The method of producing gasoline of high anti-knock rating from naphtha and olefin-con- 'taining gases free of hydrogen and methane,

which comprises charging a mixture of said gases and naphtha to a heating zone andheating the same to a temperature of 900-1100 F. while under a pressure of 750-2000 lbs. per square inch for a period 'of time sufficient to simultaneously convert the naphtha and olefin-containing gases into high knock rating gasoline fractionating the total converted material to obtain low boiling uncon-- densed gases, high knock rating gasoline and a fraction of hydrocarbons intermediate in volatility between the low boiling uncondensed gases and high knock rating gasoline,'and returning the said intermediate fraction for reprocessing.

5. In the process of producing gasoline of high knock rating from low knock rating naphtha and normally gaseous olefinic hydrocarbons, the steps comprising compressing a hydrocarbon gas containing olefins to 100-3000 pounds per square inch, removing hydrogen and methane from said compressed gases to concentrate the olefine content thereof to at least 25% olefins, charging said concentrated olefinic gas with said low knock rating naphtha to a reaction zone maintained at a temperature'between 900-1200 F. and under a pressureof 750 to 3000 pounds per square inch for a period of time sufiicient to simultaneously convert the low knock rating naphtha and gaseous olefinic hydrocarbons into high knock rating gasoline, fractionating the total converted material to obtain low boilinguncondensed gases, high knock rating gasoline and a fraction of hydrocarbons intermediate in'volatility between the low boiling uncondensed gases and high knock rating gasoline, and returning the said intermediate fraction of hydrocarbons for reprocessing.

6. In the process of producing gasoline of high knock rating from low knock rating naphtha and normally gaseous olefinic hydrocarbons, the steps comprising separating hydrogen and methane from a compressed hydrocarbon gas mixture containing olefinsso as to concentrate the olefinic content thereof, charging said concentrated olefinic gases with said low knock rating naphtha to a reaction zone maintained at a temperature within the range of 900 to 1200 F.

and to a pressure of 750 .to' 3000 pounds per square inch for a period of time suflicient to simultaneously convert the low knock rating naphtha and gaseous olefinic hydrocarbons into high knock ing gasoline, and returning the said'intermediate fraction of hydrocarbons for reprocessing.

7. In the process of producing gasoline of high the range of 900 to 1200 F. and under a pressure of 750 to 3000 lbs. per square inch for a period of time suflicient to simultaneously convert the low knock rating naphtha and gaseous olefinic hydrocarbons into high knock rating gasoline, rectifying the converted material to obtain low boiling uncondensed gases, high knock rating gasoline and a fraction of hydrocarbons intermediate in volatility between the low boiling uncondensed gases and high knock rating gasoline, and returning the said intermediate fraction of hydrocarbons to the scrubbing step for reprocessing.

8. A process of. converting and stabilizing naphtha containing substantial quantities of hydrocarbons too unstable to be incorporated in motor fuels, which comprises subjecting the said mediate in volatility between the low boiling uncondensed gases and motor fuel, and returning thesaid intermediate fraction for reprocessing. 9. A process for converting and stabilizing naphtha containing substantial quantities of hydrocarbons too unstable to be incorporated in motor fuels which comprises subjecting the said naphtha to conversion temperatures of 900 to 1150. F. whereby at least a portion of the said hydrocarbons which are too unstable to be incorporated in motor fuels are converted to materials which are sufflciently stable to be incorporated in motor fuels while simultaneously reforming that portion of the said naphtha which was sufliciently stable originally to be incorporated in motor fuels, rectifying the total converted material to obtain low boiling uncondensed gases, motor fuel and a fraction intermediate in volatility between the fixed gases and motor fuel, and returning the said intermediate fraction for reprocessing.

10. A process for converting and stabilizing a mixture of hydrocarbon materials, at least. a substantial portion of which is sufficiently stable to be incorporated in motor fuel and a portion of which is of lower boiling range and too unstable to be incorporated in motor fuel, which comprises subjecting the said admixture to conversion conditions such that at least a portion of said hydrocarbons which vare too unstable to be incorporated in motor fuels are converted to materials which are sufliclently stable to be incorporated in. motor fuels while simultaneously reforming that portion of the said hydrocarbons which was sufliciently stable originally to be incorporated in motor fuels, rectifying the total converted material to obtain uncondensed gases, motor fuel and a fraction intermediate in volatility between the uncondensed gases and motor fuel, and returning the said intermediate fraction for reprocessing.

11. A process for converting and stabilizing a mixture of hydrocarbon materials, at least a substantial portion of which is sufficiently stable to be incorporated in motor fuel and a portion of which is of lower boiling range and too unstable of the said hydrocarbons which was sumcie'ntly stableoriginally to be incorporated in motor fuels, rectifying the total converted material to obtain uncondensed gases, motor fuel and a fraction intermediate in volatility between the uncondensed gases and motor fuel, and returning the said intermediate fraction for reprocessing.

12. A process for converting and stabilizing'a mixture of hydrocarbon materials, at least a substantial portion of which is sufliciently stable to be incorporated in motor'fuel and a portion of which is of lower boiling range and too unstable to be incorporated in motor fuel, which comprises subjecting the said admixture to conversion temperatures'and to a pressure between 750 pounds per square inch and 3000 pounds per square inch, whereby at least a portion of the said hydrocarbons which are too unstable to be incorporated in motor fuels are converted to materials whichare suflicientlyrstable to be incorporated in motor fuels, while simultaneously reforming that portion of the original material which was sufliciently stable originally to be incorporated in motor fuels, rectifying the total converted material to obtain uncondensed gases, motor fuel and a fraction intermediate in volatility between the uncondensed gases and motor fuel and returning the said intermediate fraction for reprocessing. V

13. A process for converting and stabilizing a mixture of hydrocarbon materials, at least a substantial portion of which is sufficiently stable to be incorporated in motor fuel and a portion of.

square inch whereby at least a portion of the said hydrocarbons which are too unstable to be incorporated in motor fuels are converted to materials which are sufficiently stable to be incorporated in motor fuels while simultaneously reforming that portion of the said hydrocarbons which was sufliciently stable originally to be incorporated in motor fuels, rectifying the total FREDERICK w. SULLIVAN, JR. ROBERT F, RUTHRUFF. 

